"A second supplement to the author's 'General synopsis,' 1781-85 ..., listing all the species treated in the original work, in the first 'Supplement' and in the present work, revising the former discussions where necessary, and adding some new species"--Zimmer
Copies have been recorded in bibliographies with either 1801 or 1802 as the publication date on the t.p. Mullens & Swann note that "some copies are dated 1801, the second 'I' in the date having apparently been inserted after it was printed."
The adjusted page count in the second group includes pages numbered 271* and 272*
The plates are numbered CXX through CXL, with additional plates numbered CXXXVI* and CXXXVIII*
"Directions for the plates": p.  (3rd group)
With: Latham, John. Supplementum Indicis ornithologici, sive, Systematis ornithologiae. Londini : Prostat apud G. Leigh, J. et S. Sotheby, York-Street, Covent-Garden, 1801. Probably issued together
Includes bibliographical references and index
Mullens, W.H. and H.K. Swann. Bib. of British ornithology
Anker, J. Bird books
Zimmer J.T. Ayer Lib.
SCNHRB copy 39088010326718 has t.p. dated "MDCCCI" [i.e. 1801]
SCNHRB copy has bookplate: Smithsonian Institution Libraries. Gift of Marcia Brady Tucker; with Tucker collection collational notes in pencil on front paste-down endpaper and t.p
SCNHRB copy has modern tan half-leather binding with black marbled paper boards; raised bands; gilt-tooled spine and spine labels